Compressor

ABSTRACT

A compressor having a shell formed by mutually coupling shell constitution members that are a closed-bottomed container-like housing and a front housing into which a drive shaft is inserted, a compression chamber forming body provided in the shell, and a coupling element for coupling and fixing the compression chamber forming body and the shell constitution member to each other. The coupling element is extended only in the region where the shell is present, and a hole in which the coupling element extends and that is formed in the shell constitution member to which the coupling element is coupled does not penetrate the shell constitution member but terminates in the wall of the shell constitution member. In the compressor, sealing ability for leakage of refrigerant can be remarkably enhanced and restrictions on external piping and apparatuses are relaxed to significantly increase the degree of design freedom.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a structure of a compressor, and specifically, to a structure of a compressor which is suitable as a compressor for compression of refrigerant provided in a refrigeration cycle.

BACKGROUND ART OF THE INVENTION

In a compressor, especially in a compressor for compression of refrigerant provided in a refrigeration cycle (e.g., a compressor provided in a refrigeration cycle of an air conditioning system for vehicles), it is desired that refrigerant leakage is surely prevented, from a point of view to prevent performance degradation of the refrigeration cycle and to keep an amount of refrigerant filled in the refrigeration cycle as small as possible. Particularly in such a case that carbon dioxide that is recently being considered as an alternative refrigerant to fluorocarbon refrigerant is used as a refrigerant, the compressor further requires the refrigerant leakage prevention function since a higher-pressure specification is required.

A structure constructed from two or three members is generally known as a shell structure in conventional compressors. In a scroll-type compressor depicted in FIG. 2, for example, shell 21 is formed by closed-bottomed container-like (cup-like) housing 21 a and front housing 21 b, and these housings 21 a and 21 b which are mutually coupled at coupling section 22 by using bolts 23 as coupling elements. Coupling section 22 requires a sealing specification for preventing refrigerant leakage, and a gasket, etc. is usually interposed. Drive shaft 24 is inserted through front housing 21 b, and shaft sealing member 25 is provided around drive shaft 24 to seal this section. Movable scroll 26 and fixed scroll 27 as compression chamber forming bodies are provided in shell 21, where movable scroll 26 is coupled to the side of drive shaft 24, and fixed scroll 27 is engaged with engagement section 28 formed on the inner surface of closed-bottomed container-like housing 21 a and is coupled with and fixed to closed-bottomed container-like housing 21 a by bolt 29 as a coupling element inserted from outside. Sheet section 30 for this bolt 29 is formed on the outer surface of housing 21 a.

In the compressor thus constructed, regions, for which a countermeasure against refrigerant leakage from the compressor should be employed, are mainly coupling section 22 of housings 21 a and 21 b, a section where shaft sealing member 25 is provided, and sheet section 30 for bolt 29. With respect to coupling section 22 of housings 21 a and 21 b, the refrigerant leakage can be prevented by interposing a gasket, etc., and as the case may be, by welding or brazing housings 21 a and 21 b. In the section where shaft sealing member 25 is provided, various improvements of sealing member 25 are proposed (e.g. Patent document 1), whereby a fairly sure sealing has become possible even for a compressor with a high-pressure specification. However, as to improvements for sealing performance of sheet section 30 for bolt 29, a particularly excellent sealing structure has not been developed, and a method is still employed such as merely interposing a sealing material or increasing a fastening force of bolt 29 or employing a release prevention for bolt 29. Because this section is opened toward outside through a bolt hole, it is desired to apply a more definitive countermeasure against refrigerant leakage. Especially, for a compressor with a high-pressure specification using carbon dioxide as refrigerant, it is desired to improve the sealing performance at this section. Further, since bolt 29 is located at a relatively outer part in a radial direction, there is also a problem that a location at which a refrigerant pipe in the refrigeration cycle is connected to housing 21 a is restricted, thereby decreasing a design freedom.

Further, there are similar requirements and problems also in another type compressor. For example, in a wobble plate type variable displacement compressor depicted in FIG. 3, shell 31 is formed by center housing 31 a which functions also as a compression chamber forming body disposed in the central part, front housing 31 b, and rear housing 31 c which is coupled to center housing 31 a via valve plate 32. For drive shaft 33, a section where shaft sealing member 34 is provided is sealed similarly in the compressor depicted in FIG. 2. Shell 31 has coupling sections 35 a, 35 b, 35 c, which are to be sealed, in a part between respective housings 31 a, 31 b, 31 c and valve plate 32, and further has parts such as bolt sheet section 37, etc. which are desired to be improved in sealing performance, even in a coupling part via bolt 36 of housing 31 c, valve plate 32 and housing 31 a, Especially, in bolt sheet section 37, etc., similarly in the compressor depicted in FIG. 2, a higher sealing performance is desired and a problem of decrease in a design freedom exists.

Furthermore, there are similar requirements and problems also in another type compressor. For example in a double-headed swash plate type variable displacement compressor depicted in FIG. 4, shell 41 is formed by housings 41 a, 41 b which function also as compression chamber forming bodies disposed in the central part, front housing 41 c and rear housing 41 d. These housings 41 c, 41 a, 41 b, 41 d have coupling sections 42 a, 42 b, 42 c which are to be sealed, and also have parts which are coupled by through bolt 43 and which are desired to be improved in sealing performance such as bolt sheet section 44, etc. For drive shaft 45, a section where shaft sealing member 46 is provided is sealed similarly in the compressor depicted in FIG. 2. In bolt sheet section 44, etc., similarly in the compressor depicted in FIG. 2, a higher sealing performance is desired and a problem of decrease in a design freedom exists. Where, the structure to couple respective housings by a through bolt as shown in FIG. 4 can be applied also to a swash plate type variable displacement compressor (e.g. Patent document 2).

Patent document 1: JP-A-2003-246976

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

Accordingly, paying attention to the above-described requirement to improve sealing performance at the hole part opened toward outside which is formed in the housing for disposing a coupling element such as a bolt, and the above-described problem of decrease in design freedom such as a restriction of external pipe connecting structure by forming the hole at the part, in the above-described conventional compressors, an object of the present invention is to provide a structure of compressor which can satisfy such a requirement and a problem.

Means for Solving the Problems

To achieve the above-described object, a compressor according to the present invention has a shell formed by mutually coupling shell constitution members that are a closed-bottomed container-like housing and a front housing into which a drive shaft is inserted, a compression chamber forming body and the shell constitution member provided in said shell, and a coupling element for coupling and fixing said compression chamber forming body and said shell constitution member to each other, and is characterized in that the coupling element is extended only in a region where the shell is present, and a hole which is formed in the shell constitution member to which the coupling element is coupled for extension of said coupling element does not penetrate the shell constitution member but terminates in a wall of the shell constitution member. A bolt can be typically used as the coupling element, but as the case may be, another coupling element can be used.

In such a structure of the compressor according to the present invention, because the coupling element like a bolt, etc. is extended only in the region where the shell is present, and the hole for extension (insertion) of the coupling element does not penetrate the shell constitution member but terminates in the wall of the shell constitution member, a hole opening outside is not provided in this shell constitution member as a hole for extension (insertion) of the coupling element, and therefore, connection bolts or bolt sheet sections, etc. in the conventional structure do not appear outside. Consequently, it becomes unnecessary to consider sealing performance in the bolt sheet sections, etc. and the requirement itself for improving the sealing performance in such a section does not exist, and the fear of refrigerant leakage in the section is completely removed. In other words, the number of sections to be sealed can be surely decreased, and the sealing performance against refrigerant leakage can be greatly improved.

Further, because the coupling element and the hole for extension (insertion) of the coupling element do not appear outside the shell constitution member, restrictions on design with respect to connection of external pipe, etc. is greatly relaxed, thereby increasing design freedom. The position disposed with the coupling element is not particularly restricted, and it may be appropriately decided in consideration of connectability of pipes from outside or easiness of installation and mounting of the compressor relative to devices or pipes therearound.

Although it may be possible to form the shell constitution member to which the coupling element is coupled, that is, the shell constitution member to which the compression chamber forming body is coupled by the coupling element, by the front housing, this shell constitution member coupled with the coupling element is preferably formed by the closed-bottomed container-like housing. By such a structure, the coupling element can be contained together with the compression chamber forming body completely in the closed-bottomed container-like housing, and it becomes possible to easily realize a closed-type structure that is desirable in sealing performance.

Such a compressor according to the present invention is suitable as a compressor provided in a refrigeration cycle for refrigerant compression, which highly requires an improvement in sealing performance, and specifically, as a compressor provided in a refrigeration cycle in an air conditioning system for vehicles. In particular, it is specifically suitable for a case where carbon dioxide requiring a high-pressure specification is used as refrigerant.

Effect According to the Invention

Thus, in the compressor according to the present invention, a sealing performance against refrigerant leakage can be greatly improved, and in addition, restrictions on external pipes or external devices can be relaxed, thereby greatly increasing design freedom.

BRIEF EXPLANATION OF THE DRAWINGS

[FIG. 1] FIG. 1 is a vertical sectional view of a compressor according to an embodiment of the present invention.

[FIG. 2] FIG. 2 is a vertical sectional view of a conventional compressor.

[FIG. 3] FIG. 3 is a vertical sectional view of another conventional compressor.

[FIG. 4] FIG. 4 is a vertical sectional view of a further conventional compressor.

EXPLANATION OF SYMBOLS

1: compressor 2: shell 2 a: closed-bottomed container-like housing 2 b: front housing 3: drive shaft 4: coupling section 5: bolt 6: cylinder block body as compression chamber forming body 7: bolt as coupling element 8: hole (hole for extension of coupling element) 9: shaft sealing member 10: crank chamber 11: swash plate 12: piston 13: shoe 14: cylinder bore 15: suction chamber 16: discharge chamber 17: suction port 18: discharge port

THE BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, desirable embodiments of the present invention will be explained referring to figures.

FIG. 1 shows a compressor according to an embodiment of the present invention, and specifically, a case where the present invention is applied to a swash plate-type fixed displacement compressor. Where, although FIG. 1 shows a case where the present invention is applied to a swash plate-type fixed displacement compressor to simplify the explanation, the present invention can be also applied similarly to a swash plate-type variable displacement compressor, or moreover, a scroll-type compressor (including both of a fixed displacement type and a variable displacement type), etc.

In FIG. 1, symbol 1 indicates the whole of the compressor. In this embodiment, shell 2 of compressor 1 is formed by mutually coupling shell constitution members that comprise closed-bottomed container-like (cup-like) housing 2 a and front housing 2 b into which drive shaft 3 is inserted. Coupling section 4 as in a conventional structure is formed between closed-bottomed container-like housing 2 a and front housing 2 b, where both housings 2 a, 2 b are mutually coupled by bolt 5. The sealing at coupling section 4 may can be performed by interposing of a gasket, welding or brazing, etc. similarly in a conventional structure.

In closed-bottomed container-like housing 2 a, cylinder block body 6 is disposed, and the cylinder block body 6 which is coupled and fixed to closed-bottomed container-like housing 2 a via bolt 7 provided as a coupling element. Bolt 7 as a coupling element is extended only in a region where shell 2 is present, especially only in a region where closed-bottomed container-like housing 2 a is present, so as not to appear outside compressor 1 at all. Further, hole 8 (expressed as a hole for extension of coupling element in the present invention) for extension (insertion) of bolt 7, formed in the shell constitution member (that is, closed-bottomed container-like housing 2 a) to which bolt 7 is coupled, does not penetrate closed-bottomed container-like housing 2 a but terminates in a wall (within the wall thickness) of closed-bottomed container-like housing 2 a. Therefore, hole 8 also does not appear outside compressor 1 at all.

In front housing 2 b, shaft sealing member 9, which is formed similarly in a conventional structure, is provided around drive shaft 3 to seal this part from outside of compressor 1.

In crank chamber 10, provided is inclination angle-fixed swash plate 11 which can rotate integrally with drive shaft 3. Swash plate 11 is disposed so as to be able to slide on a pair of shoes 13 held by piston 12 at a contact condition therewith, and a rotational movement of swash plate 11 accompanied with a rotation of drive shaft 3 is converted into a reciprocating movement of piston 12 via the sliding contact with the pair of shoes 13. Piston 12 is reciprocated in cylinder bore 14 formed in cylinder block body 6 and discharges fluid into discharge chamber 16 after compressing the fluid (especially, refrigerant) sucked from suction chamber 15. Symbol 17 indicates a suction port connected with an external pipe, and symbol 18 indicates a discharge port connected with an external pipe, respectively. A refrigeration cycle (not shown) is formed via the connection with these external pipes.

In thus constructed compressor 1, because bolt 7 as a coupling element is extended only in a region where shell 2 is present, specifically only in a region where closed-bottomed container-like housing 2 a is present, and hole 8 formed in closed-bottomed container-like housing 2 a for insertion and fastening of bolt 7 is formed as a non-penetration hole, a structure where neither bolt 7 nor hole 8 appears outside closed-bottomed container-like housing 2 a is realized. Namely, any hole opening outside other than suction port 17 and discharge port 18 is not provided on the outer surface of this closed-bottomed container-like housing 2 a, and a bolt sheet section, etc. in a conventional structure does also not exist on the outer surface of closed-bottomed container-like housing 2 a. Therefore, the subject matter on improvement in sealing performance for bolt sheet section, etc. as in a conventional structure does not exist, namely, the subject matter on improvement in sealing performance originating from existence of bolt 7 disappears, and therefore, there is not a problem on refrigerant leakage originated from existence of bolt 7 at all. The internalization of bolt 8 can surely reduce the number of sections to be sealed. Consequently, because it is enough to consider sealing performances only for coupling section 4 and for the section of shaft sealing member 9 the sealing technologies of which have been already established, conventional technologies can sufficiently handle the sealing performances for these sections. By this, refrigerant leakage can be surely prevented, and even for a high-pressure specification in such a case as using carbon dioxide as a refrigerant, it becomes possible to surely prevent refrigerant leakage.

Further, because both of bolt 7 and hole 8 do not appear outside closed-bottomed container-like housing 2 a, restriction on design with respect to external pipe connection, etc., such as restriction on positions of suction port 17 and discharge port 18, can be greatly relaxed, thereby increasing design freedom.

Where, as aforementioned, since the embodiment depicted in FIG. 1 shows merely an example of a compressor which is applied with the present invention, the present invention is not limited to this example at all. The present invention can be applied to other type compressors such as ones depicted in FIG. 2-FIG. 4, and further to other type compressors that are not depicted.

INDUSTRIAL APPLICATIONS OF THE INVENTION

The structure of the compressor according the present invention can be applied substantially to any type compressor, and specifically, it is suitable for a compressor provided in a refrigeration cycle of an air conditioning system for vehicles, in particular, for a compressor provided in a refrigeration cycle using carbon dioxide refrigerant which requires a high-pressure specification. 

1. A compressor having a shell formed by mutually coupling shell constitution members that are a closed-bottomed container-like housing and a front housing into which a drive shaft is inserted, with a bolt which is inserted from a side of said front housing into an insertion hole extended from said front housing to a wall of said housing, a compression chamber forming body provided in said shell, and a coupling element for coupling and fixing said compression chamber forming body and said shell constitution member to each other, characterized in that said coupling element is extended only in a region where said shell is present, and a hole which is formed in said shell constitution member to which said coupling element is coupled for extension of said coupling element does not penetrate said shell constitution member but terminates in a wall of said shell constitution member.
 2. The compressor according to claim 1, wherein said shell constitution member which is coupled to said coupling element comprises said closed-bottomed container-like housing.
 3. The compressor according to claim 1, wherein said coupling element comprises a bolt.
 4. The compressor according to claim 1, wherein said compressor is a compressor for compression of refrigerant provided in a refrigeration cycle.
 5. The compressor according to claim 4, wherein said compressor is a compressor for compression of carbon dioxide. 